Prefabricated conduit



March 10, 11%42. w a SOMERs 2,275,5Y2

PREFABRICATED CGNDUIT Filed May 2, 1939 4 sheets-sneak 1Mi'llkna-smew's,

March 10,1942. w. s. SOMERS 2,275,572

PREFABRIGATED CONDUIT Filed May 2, 1959 4 Sheets-Sheet 2 qyigy.

March 10, 1942. w. SOMERS 2,275,572.

PREFABRI CATED CONDUIT Filed May 2, 1959 4 Sheets-Sheet 4 (34 1920. V MW54 17/121 8. Sent-8B,

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Patented Mar. 10, .1942

,UNITED STATES PATENT OFFICE 2,275,572 PREFABRICATED CONDUIT William S.Somers, Columbus, Ohio Application May 2, 1939, Serial No. 271,416

9 Claims.

This invention relates. to the sheet metal art and is particularlydirected to the formation of sheet metal conduits for the transfer ofheating and cooling mediums employed in air conditioning systems forbuildings. Prior to this invention, when air conditioning systems werebeing installed, it was necessary for a sheet metal worker to cut, formand fit certain of. the required conduits at the time and place ofinstallation. These operations usually require a considerable amount oftime and greatly increase the final cost of the system. 7

The primary object of the present invention resides in the provision ofsheet metal duct forming means which may be completely constructed atthe factory in stock sizes, shippedv in a knockclown condition, andassembled at the location of the installation without alteration.

A further object rests in providing improved conduit sections andcoupling members therefor which are simple to manufacture and can bequickly and easily assembled to produce substantially air-tight ducts.

Another object is the provision of a conduit forming section which canbe manufactured in a plurality of standard sizes from combinations ofwhich a large number of conduits of different sizes may be produced, thenumber of sizes being further increased by performing slight alterationsconsisting of straight cutting operations on the standard sections.

A still further object resides in the formation of conduit formingsections which may be stacked or nested to conserve space duringshipping and storage prior to use.

It is also an object to form a sectional conduit, having completelyclosed longitudinally extending corners and means for connecting thesections. without the use of tools, screws or other equipment.

Other objects will be apparent from the following description and theaccompanying drawings. in which the invention has been illustrated indetail.

Fig. 1 is a perspective view of a. portion of a duct formed inaccordance with the present invention;

Fig. 2 is a vertical transverse sectional View taken through the ductshown in Fig. 1;

Fig. 3 is a similar view illustrating how the size of the duct may bereduced by a simple cutting operation;

Fig. 4. is a detail sectional View taken through the joint between theflanges of a pair of conduit forming members;

Fig. 5 is a similar view of a slightly modified form;

Fig. 5a, is a similar View of a further modified form;

Fig. 6 is a vertical longitudinal sectional View taken through the jointbetween a pair of duct sections, the plane of this figure beingindicated by the line VI-VI of Fig. 1;

Fig. '7 is a similar View of a slightly modified form of connectingmember;

Fig. 7a is a similar view of a further modified form of connectingmember;

Fig. 8 is a plan view of a portion of a duct having a reducer positionedtherein;

Fig. 9 is a similar View showing a reducer having one straight side;

Fig. 10 is a similar View showing an increaser provided with a pluralityof take-off fittings;

Fig. 11 is a horizontal sectional view taken through the conduit at thepoint where a takeoff is connected thereto;

Fig. 12 is a detail sectional view taken on the plane indicated by theline XII-XII of Fig. 8;

Fig. 13 is a plan view of a portion of a large size conduit constructedof sections embodying a modified form of the invention;

Fig. 14 is a transverse sectional view on the plane indicated by theline XIVXIV of Fig. 13;

Fig. 15 is a perspective View of the complemental ends of a pair ofcoupling bars in a separated condition;

Fig. 16 is a plan view of a trunk conduit provided with a plurality ofreducing sections, the latter members having take-off fittings connectedtherewith;

Fig. 17 is a horizontal. sectional View taken through an increaser orreducer and a take-cit fitting connected therewith;

Fig. 18 is a transverse vertical sectional view of a modified form ofconduit;

Figs. 19 and 20 are transverse sectional views taken through the seamsbetween the conduit sections showing different methods by which thesections may be locked in assembled relation.

Referring more particularly to the drawings, the numeral l designates aconduit formed from sections 2. constructed in accordance with thepresent invention. Each section 2 is formed to include a pair ofchannel-shaped members 3' arranged with the open sides toward oneanother. The members 3 include vertical side walls 4 and horizontalwalls 5 and 6. When one of the channel members is turned to position theopen side toward that of the. other channel, the wall 6 is brought intoregistration with the wall 5 of the second member. The free edge of thewall 6 is folded upon itself a plurality of times, as indicated at l, toform a longitudinally extending groove at the outer edge of the flange.The folded portion is offset by bending the flange as at 8 to positionthe channel in alignment with the flange 6. The outer edge of the flange5 is plain and unfolded in order that it may be inserted in the groovein flange 6 when the members are assembled. The channel members are heldin their assembled relation by a coupling member 9 which is formed froma plurality of bars It and II of different lengths. The bars H aredisposed at the sides of the conduit and connect the side walls 4 of thesections.

As illustrated in Fig. 6, the bars It and H are formed of inner andouter strips [2 and I3 welded or otherwise joined along theirlongitudinal axis. The side portions of the strip I3 are oifset as at Mto space them from the outer edge portions of the strip l2. Thisconstruction provides the barwith longitudinally extending channels atthe side edges for the reception of the ends of the conduit sections.The edges of the strip l2 are turned under as at 55 to provide inwardlydirected shoulders which engage spring tongues it formed at the ends ofthe channel members 3. The seam produced by the formation of the groovein the flanges 6 is relieved at the ends of the members 3 toaccommodate'the bars it). Prior to fastening the bars H) and III to theconduit section, these members are connected at their ends to form anendless collar or coupling, after which they are applied to an end ofthe assembled channel members.

The bars H are provided With angularly directed tongues lia'at theirends which, when the bars are assembled into collar forming position,enter the ends of the bars and a spring lug lib formed on the tonguesnaps into an opening la in the bar It] as shown in Fig. 12. When thisoccurs, the bars will be securely held in assembled relation. They maybe disassembled when desired by raising the portion of the barimmediately in front of the lug lib to permit it to be released from theshoulder provided by the edge of the opening.

The application of the collar is facilitated by starting one corner ofone end of the duct section in the groove of the collar and followingaround the duct one side at a time. After the end of the duct has beenstarted intothe groove, the collar may be permanently attached to thesection by pushing the members together until the spring tongues on themembers 3 snap behind the shoulders formed in the groove. Usually whenthe duct is being assembled, the channelshaped members are connected toform a section, then a collar is applied to one end of each section.When the sections are assembled to form the duct, the plain ends of thesections are slipped into the grooves of the collars on the othersections.

In certain instances, the members 3 are formed as shown in Fig. 3wherein the flange is short, thus positioning the seams at thelongitudinal corners of the conduit. When this type of duct formingsection is employed, the bars from which the collars are formed may beattached directly to the ends of the members and shipped therewith;After assembly, the edges ofthe flanges 5 are inserted inthechannels ofthe seams on flanges ti and the sections pushed together and the'bars l0and H will be fastened by snap locks formed at the ends thereof.

In Figs. 8, 9 and 10, there has been illustrated different types offittings formed from conduit sections constructed in accordance with theinvention. These fittings embody one or more expanding or reducingsections [1 which correspond to the channel members 3 except that thedepth of the channel varies from one end to the other. When two of thesections are placed together as shown in Fig. 8, a center increaser orreducer is produced. The edges of the flanges of the sections I!correspond with those on the channel members 3 and one of the lattermembers may be combinedwith one of the former to produce a straight sideincreaser or reducer. As illustrated, the degree of variation in depthof the members I! may be changed according to the change in size of theconduit.

In Fig. 10, a center increaser has a plurality of take-off connectionssecured to its larger end. Any desirable take-ofi fitting may be used atthis point but for purposes of illustration, a top takeoff fitting I8 isprovided at one side while a side take-off fitting i9 is connected atthe other side. Between these fittings, a straight duct l continues onfrom the increaser.

Fig. 11 shows the connections between a takeoff fitting, an increaserand a straight duct I leading from the increaser. The side wall of thestraight duct section has a U-shaped strip 20 connected at its edge.This strip receives the forward edge of the inner side wall of thetakeoff fitting and prevents the escape of air through the space betweenthese members. The other edges of the take-off fitting are connectedwith the end of the increaser by the usual collar formed from the barsI0. In this type of connection, the straight duct section is joined withthe collar only at the top and bottom.

In Fig. 13, an extra large conduit provided with a center increaser hasbeen illustrated. This large conduit is constructed from parts corresponding to those employed in making the conduit I but these parts areseparated by substantially flat sheets 2| positioned between the flangesof the channel members 3.

As illustrated in Fig. 14, the plates 2| have one plain side edge andone provided with a longitudinally extending groove identical with thatformed on the flange 6 of the channel member 3. The plain edge of theplate 2! is positioned in the groove provided at the edge of the-member3. This produces a Wide duct from the standard parts used in theconventional ducts merely by the addition of the flat plates 2!. Tostrengthen this large duct longitudinally, the folded edge of the flange6 has an upwardly directed rib 22 pr0- vided at the edge of the grooveby continuing the metal upwardly and terminating'it in a downwardextension. This type of seam has been illustrated in Figs. 5 and 14.

The collar members used with this type of duct are also strengthened bythe addition of avertical rib 23 illustrated in Figs. '7 and 14. Thisrib may be formed from separate strips attached to the bars H] or it maybe formed by doubling the strip 12 in the middle and then flattening theside portions to provide flanges. This rib maybe provided at its endswith openings 24 through which wires or other securing devices may bepassed to anchor the conduit to an overhead support. When thecollarsectionsare provided with the longitudinally extendingreenforcingrib, the openings for the reception of the spring means onthe side bars are positioned at either side-of the longitudinal centerof the bars. Otherwise,

these collars are identical in construction with the standard collarillustrated in Figs. 6 and 15. The bar shown in Fig. 7 has the lowerplate formed from an unfolded strip of material while the upper bar isbent downwardly at its longi tudinal center to provide the spacing atthe side edges of the strips. By this provision, the inner surface isdevoid of shoulders which would interfere with the flow of air throughthe conduit.

In Fig. a, the conduit section having the groove formed at its edge hasall the material disposed at one surface of the flange. In other words,when the material is folded upon itself to form the groove, the flangeis not bent as in the preferred form but is permitted to remain fiatuntil the first fold at the edge 'of the groove is formed. The free edgeof the opposite flange is ofiset as at 25 to provide the conduit formedby the joining of these two sections with a smooth inner wall whichwill. cause no interference with the air passing therethrough.

In Fig. 7a, a connecting bar for the ends of the conduit section hasbeen provided from a single strip of sheet metal. In this form ofconnecting member, the strip is doubled as at 26 and the por tionsfolded under or rebent as at 21 to form the inner flanges 28 of theconnecting bar. The flanges 28 are spaced from the body of the barformed by folding the bar at 26 to provide grooves for the ends of theconduit sections connected therewith. The body of the bar is formed withperforations adjacent the edges of the groove to receive the springtongues formed on the conduit sections. If desired, this type of bar maybe welded along the folded portion at 2'! to make the bar more rigid.

. In Fig. 16, the trunk conduit 29 is provided with'a plurality ofreducers 36. At its widest portion, the trunk line is provided with atop take-off connection3l leading to one side of the conduit. Eachreducer has an angular take-off fitting 32 or 33 secured thereto. Asshown in Fig. 1'7, the take-on fittings have one end provided with aperipheral flange through which screws extend to hold the fitting withthe side wall of the reducer. The flanges are spaced slightly from theend of the take-off fitting to permit this end to enter the reducerthrough an opening formed in the side wall.

In Fig. 18, a conduit has been illustrated in which there has beenformed a pair of duplicate sections 34 which are spaced by plain fiatplates 35. The sections 34 are channel shaped and have the free edges ofeach flange provided with grooves formed in the same manner as thegroove on the flange 6 of the preferred form of conduit. The edges ofthe material from which the groove is formed are provided with thereenforcing ribs which serve to strengthen the conduit and to preventlongitudinal flexing.

In Figs. 19 and 20, there has been shown several methods of securing theconduit sections to one another. In Fig. 19, the free edge of one fiangehas the usual groove formed therewith. One wall of. the groove has anopening 35 formed therein through which a tongue 31 provided on theflange of the other section extends. This tongue is bent back to providea hook which will lock the sections in assembled condition.

In Fig. 20, the plain flange has a rearwardly directed spring tongue 38thereon to engage the edge of the opening formed in the wall of thegroove on the other flange. These methods of securing the conduitsections together are employed when it is desired to make the conduit 1.In a sheet metal duct of the type having a plurality of tubularsections, means for connecting the ends of the sections comprising acoupling formed of a plurality of bars, each of which has alongitudinally extending groove in each side edge, cooperative meansprovided on said bars for detachably connecting the ends thereof to.

form an endless collar, and inwardly directed shoulders formed on saidbars within said grooves.

2'. In a sheet metal duct of the type having a pair of tubular sections,coupling means for connecting said sections comprising a plurality ofbars each of which is formed from a pair of strips joined alongthelongitudinal axes thereof, the side edges of the strips being spacedto provide a groove at each longitudinal edge of said'bar, certain ofsaid bars being provided with a socket at each end, and tongue meansformed at the ends of the other bars for reception by the sockets in thefirst bar.

3. In a sheet metal duct of the type having a pair of tubular sections,coupling means for connecting said sections comprising a plurality ofbarseach of which is formed from a pair of strips joined along thelongitudinal axes thereof, the side edges of the strips being spaced toprovide a groove at each longitudinal edge of said bar, certain of saidbars being provided with a socket at each end, shoulder means formed onthe last-mentioned bars at one side of each socket, tongue means formedat the ends of the other bars for reception by the sockets in the firstbars, and lug means projecting from said tongue means for engagementwith said shoulders to resist separation of said bars.

4. In combination with a sheet metal duct of the type having a pair oftubular sections, coupling means for connecting said sections comprisinga plurality of bars each of which is formed from a pair of stripsadapted to be det-achably connected at their ends to form a collar, oneof said strips having the longitudinal side portions offset with respectto the central portion of said strip, said central portion being securedto the central portion of the second strip, the side edges of saidsecond strip being folded under upon said strip, the offsetting of theside portions of said first strip providing the bar with a groove ateach side, the folded portions of said second bar providing inwardlydirected shoulders in said grooves.

5. In a sheet metal duct of the type having a pair of tubular sections,each section being composed of a pair of oppositely arranged channellikemembers having interfitting longitudinal edges, coupling means forconnecting the sections and preventing separation of the members ofeachsection comprising a plurality of bars, each of which has alongitudinally extending groove at each longitudinal edge for thereception of an end edge of one of said tubular sections, means disposedin said grooves for holding the section edges therein to prevent therelease of said sections from said bars, and interlocking means formedon the complemental ends of said bars, connection of the ends of thebars providing an endless collar and preventing separation of thechannel members of said sections.

6. In a sheet metal duct of the type having a pair of tubular sections,coupling means for connecting said sections comprising a plurality ofbars each of which is formed from a pair of strips joined along thelongitudinal axes thereof, the side edges of the strips being spacedtoprovide a groove at each longitudinal edge of said bar, and cooperativemeans provided on said bars for detachably connecting the ends thereofto for an endless collar. V

7. 'Ina sheet metal duct of the type having-a pair of duplicative'separable sections provided with means on the adjoining longitudinaledges thereof to effect their connection to form a conduit, meansdetachably secured to the ends of said sections to prevent separationthereof, said means comprising a plurality of bars each of which isformed from a pair of strips joined along the longitudinal axes thereof,the side edges of said strips being spaced to provide a groove at eachlongitudinal edge of said bar, and cooperative means provided on saidbars vfor detachably connecting the ends thereof to form an endlesscollar.

8. In a sheet metal duct system, a pair of oppositely disposedduplicative separable conduit sections having ends of unequal width,interfitting means provided on the adjoining longitudinal edges of saidsections, a-plurality of separate conduit members disposed inregistration with the wider ends of' said sections and means forpreventing separation of said sections and connecting said conduitsthereto, said means comprising a plurality of bars each of which isformed from a pair of strips joined along the longitudinal axes thereof,the side edges of said strips being spaced to provide a groove at eachlongitudinal edge of said bar, said grooves being formed-forthereception of edges of said sections and said conduit members, means insaid grooves for engaging the edges positioned therein to prevent theaccidental release thereof, and cooperative means provided on said barsfor detachably connecting the ends thereof to form an endless collar,said collar preventing separation of said duplicative sections.

9. In a sheet metal duct system, a pair of oppositely disposedduplicative separable conduit sections having ends of unequal width,interfitting means provided on the adjoining longitudinal edges of saidsections, a plurality of separate conduit members positioned with theirinlet ends in side by side relation and disposed in registration withthe Wider ends of said sections, U-shaped strip means engaging theadjacent forward edges of said conduit members, and means for preventingseparation of said sections and connecting said conduits thereto, saidmeans comprising a plurality of bars each of which is formed from a pairof strips joined along the longitudinal axes thereof, the side edges ofsaid strips being spaced to provide a groove at each longitudinal edgeof said bar, said grooves being formed for the reception of edges ofsaid sections and said conduit members, means in said grooves forengaging the edges positioned therein to prevent the accidental releasethereof, and cooperative means provided on said bars for detachablyconnecting the ends thereof to form an endless collar, said collarpreventing separation of said duplicative sections.

1 WILLIAM S. SOMERS.

